INVESTIGATION OF DIFFERENT EXTRACTION METHODS FOR HEMP SEEDS

Abstract

Industrial hemp hearts were subjected to four different laboratory (research) scale solvent extraction techniques including soxhlet extraction, microwave pretreated soxhlet extraction, ultrasound extraction, and microwave extraction as well as extraction by non-solvent mechanical cold pressing. The maximum extraction yield of 54 % (w/w) was observed for both microwave as well as microwave pretreated soxhlet extracted seeds and the minimum run time of 30 minutes were noted for both ultrasound extraction and microwave extraction. The ratio of Linoleic acid to Linolenic acid was found to be close to 3:1 which is considered to be optimal for nutrition. Also, the ratio of unsaturated fatty acids to saturated fatty acids was in the range of 6.7 to 9.1. Several minor compounds like ɣ-Sitosterol, stigmasterol, rhodoxanthin, carotene and methyl cholate were identified in the oils which have not been previously reported. Antioxidants β-Carotene and ɣ-Tocopherol have also been identified in the oil sample. Moreover, the acid value, iodine value and oxidative stability of the oils indicated that the oil was of an improved quality and that the level of unsaturation was very high. The poly unsaturated fatty acids (PUFA) found in the oils have numerous health benefits, the most important being improvement of cardiovascular health. A perfect combination of unsaturated fatty acids and saturated fatty acids and an appropriate medley of different antioxidants not only qualifies hemp seed oil as an excellent source of nutrition, but also as an important plant based (vegetable) oil for the higher value nutraceutical and pharmaceutical industries.